The original Planetfall is sci-fi text-adventure written by Steve Meretzky, published by Infocom for DOS PCs in 1983. As we can read on Wikipedia:
“The game starts with the user assuming the role of a lowly Ensign Seventh Class on the S.P.S. Feinstein, a starship of the Stellar Patrol. Overbearing superior Ensign First Class Blather assigns the player to mop decks, not exactly the glorious adventures promised by the recruiters on Gallium. But a sudden series of explosions aboard the ship sends the player scrambling for an escape pod, which eventually crash-lands on a nearby planet. There are signs of civilization, but curiously no traces of the beings that once lived there. Eventually encountering a helpful but childlike robot named Floyd, the player must unravel the mysteries of the single deserted structure on the planet, Resida, and find a way to get back home.”
3 years later the company was bought by Activision and in the mid ‘90s they tried to create a sequel titled: Planetfall 2: Floyd’s Next Thing. The project was started at least a couple of times, but it was always cancelled in the end.
Two trailers were released promoting the two versions of the sequel: the first one looked a bit like Myst, with per-rendered graphics, while the second version of the game was in full, real-time 3D.
In 2012 Archive.org user Swizzley uploaded a playable demo of Planetfall 2 and another prototype was later uploaded in 2016 by Agustin Cordes. As we can read from the file description:
“Don’t get your hopes up: this is a very early prototype from the cancelled sequel to Infocom’s classic text adventure. It’s barely playable, though it does provide an interesting look at how the game would have played with a realtime 3D engine. The prototype does introduce a puzzle (at least the only one I could find) and features voice acting as well as a pretty cool soundtrack tune. Judging by the puzzle, you were able to give orders to your robot companions similarly to how Infocom’s classic text adventures worked.
[…] back in 2007, an alleged ex-employee from Activision was auctioning this CD on eBay. He couldn’t verify the contents of the disc, but many enthusiasts including myself still pledged hoping it was legit. My top bid was $40 (hey, it was a pretty decent sum at the time) but the CD was sold at a whooping $90. I wasn’t going to give up, so I contacted the seller who in turn put me in touch with the buyer. Turns out he was a nice guy who exchanged the same ISO I’m uploading right now for a physical soundtrack of Scratches and a signed copy of the game. It was a fairly good deal. This prototype brings back great memories.
It’s been almost ten years since that transaction happened, and I think the time has come to properly preserve this rare piece of software history. Enjoy!”
A note on those two demos mentioned above. The first demo is “non-interactive” so it is not a “playable” demo in that sense. It just runs like a movie in DOS. The second demo I never could get to run in Windows 9x even on a native Win9x system. I think it is very picky about graphics drivers, etc., but by all means please give it a shot and if you do get it to run, please leave a post here on what combination you used to accomplish that.